Effects of morphine on the scalp EEG and FDG PET scans are being compared to determine the brain areas invoked in euphoria. Etiology collected in past years and is now analyzing the EEG data from 20 scalp locations from post addicts receiving placebo, 15 and 30 mg injections of morphine. These subjects subsequently received FDG PET scans while receiving placebo and 30 mg of morphine. The PET scans are performed by our collaborators. The EEG data by itself provides insight into time course of electrophysiologic effects of a mu agonist in humans and the cortical distribution of mu effects. PET techniques do not by themselves provide information about the time course of the mu effects. In the preliminary analysis, twelve subjects had increased EEG delta and the theta power beginning 15 minutes and persisting until 45 minutes after the intramuscular injection. Changes in artifact detection were being investigated so that the relationship between these EEG changes and subjective effects of morphine can be investigated.